It’s embarrassing when you’re an editor to find errors in your own writing. Even so, it’s reassuring in an odd way. I tell people all the time that it’s virtually impossible to edit and proof your own stuff to the degree a third party can, particularly a professional.
And then I see that I have proven my own point, albeit unintentionally.
It’s more embarrassing when other people in your business see the mistake. Despite the fact we all know it can happen to us, we seem to have an inborn instinct to sneer at errors. And some people believe that’s what you mean by pointing out an error — that the subtext is “Ha, ha. Got you.”
Which is why I always deliberate before pointing out an error in someone else’s published work. I put it on the level of pointing out that someone has food in their* teeth or a label sticking out in the back of their* blouse. When would I point that out? To a friend or family member, probably anytime. To strangers? Only if they were getting ready to speak in public and I don’t think, from their demeanor, that they would be thrown off-balance.
But it’s still risky. And you need to know that what you want to point out is a universally accepted issue. Serial commas — would be unlikely to say anything about. Spaces around em-dashes — same thing. In either case, it depends on what style guide you are using.
And then there’s the problem I asterisked (*) above. “Someone” traditionally takes the third person singular: “he” or “she.” But because of our awareness of sexism, neither seems a great solution. “It” fits the bill, but just sounds weird to native speakers; “they” is what we tend to use in spoken language. So, yes, I know the rule, but I have made a conscious choice to ignore it. I predict that the use of “they” in this context will someday become the rule, possibly before I die. When it’s my call, I use it, although generally with a note like this to prove I do know the rule, I just don’t care for it.